Search results for "evolutionary"

Remarks on biology, vocalisations and systematics of Urocynchramus pylzowi Przewalski (Aves, Passeriformes)

2006

Several field studies in the Qinghai Nanshan area (Qinghai Province, China) have added new findings to the scant knowledge about Przewalski´s Rosefinch Urocynchramus pylzowi Przewalski, 1876. The hitherto completely unknown vocalisations are described and used to clarify systematic relationships. Although one could argue for a relationship to Uragus sibiricus (Pallas), based on nearly identical auditory impression and sonagram structures of their songs, detailed measurements show significant differences in time and frequency parameters. Moreover a mtDNA analysis shows no close phylogenetic relationship to either of three major emberizid clades. These results support the hypothesis that Uroc…

Allozymic variation and divergence in three species of Antirrhinum L. (Scrophulariaceae-Antirrhineae)

1999

Abstract An allozymic study of three wild species of Antirrhinum L.—A. lopesianum RothmA. mollissimum Rothm. and A. microphyllum Rothm.—is described. All are members of subsectionKickxiella Rothmand are narrow-range endemics of the Iberian Peninsula. The variability of the different loci, as well as the number and mobility of the alleles, differ among the three species, a demonstration of the usefulness of allozymes for the systematics of the genus. The finding of alleles unique to each species indicates high divergence among species suggesting ancient diversification, and supports the hypothesis of a geographical model of speciation. All three species show high levels of within-species var…

Evolutionary transitions in broad tapeworms (Cestoda: Diphyllobothriidea) revealed by mitogenome and nuclear ribosomal operon phylogenetics

2021

Abstract Broad tapeworms (Diphyllobothriidea) are parasites whose adults are capable of infecting a wide range of freshwater, marine and terrestrial tetrapods including humans. Previous works examining the evolution of habitat and host use in this group have been hampered by the lack of a well-resolved phylogeny. In order to produce a robust phylogenetic framework for diphyllobothriideans, we sequenced the complete mitochondrial genome of 13 representatives, carefully chosen to cover the major clades, and two outgroup species representing the Spathebothriidea and Haplobothriidea. In addition, complementary data from the nuclear ribosomal operon was sequenced for 10 representative taxa. Mito…

Phylogeny of Veronica in the Southern and Northern Hemispheres based on plastid, nuclear ribosomal and nuclear low-copy DNA

2010

The cosmopolitan and ecologically diverse genus Veronica with approximately 450 species is the largest genus of the newly circumscribed Plantaginaceae. Previous analyses of Veronica DNA sequences were in stark contrast to traditional systematics. However, analyses did not allow many inferences regarding the relationship between major groups identified, hindering further analysis of diversification and evolutionary trends in the genus. To resolve the backbone relationships of Veronica, we added sequences from additional plastid DNA regions to existing data and analyzed matching data sets for 78 taxa and more than 5000 aligned characters from nuclear ribosomal DNA and plastid DNA regions. The…

Ammonites phylogenetic analysis: state of the art and new prospects

2004

Abstract Two main types of data are available to resolve phylogenies using fossils data: (1) stratigraphic ordering of taxa, and (2) morphological characters. In most phylogenetic studies dealing with ammonites, authors have given priority to the stratigraphic distribution of taxa. This practice is classically justified by the fact that the ammonite fossil record is frequently outstandingly good. In practice, the level of integration of stratigraphic and morphologic information in a single analysis depends on the confidence that authors have in the quality of data. Besides, many evolutionary concepts, which could differ over time and between authors (e.g. anagenesis, cladogenesis, iterative…

Classification and Phylogeny of the Triatominae

2010

Publisher Summary Perhaps the greatest challenge for the classification of Triatominae is the lack of a unifying concept of species. To discuss some of the conflicts that arise from applying modern concepts to traditional classification, and to highlight some recurrent practices regarding the systematics of the subfamily, this chapter develops this discussion in parallel with the traditional and modern concepts of species. In understanding biodiversity, one must understand that taxonomy and systematics work together, although the two terms are often confused. Divergence between the modern concepts of systematics starts at the definition given to the taxa they wish to analyze: single individ…

An overview of the phylogeny of the families Lafoeidae and Hebellidae (Hydrozoa:Leptothecata): their composition and classification

2006

A cladistic analysis of the genera of the family ‘Lafoeidae’ was performed in order to investigate suprageneric classifications and the boundaries of the family, as well as to organise the available morphological data and discuss the possible evolution of some morphological characters. Our results suggest that the former ‘Lafoeidae’ must be separated into two families: the Hebellidae and the Lafoeidae (including the subfamilies Lafoeinae and Zygophylacinae).

Towards a complete phylogeny of African Melastomateae : systematics of Dissotis and allies (Melastomataceae)

2020

Local adaptation, coadaptation, and population boundaries

1986

Coadaptation can occur either because of local adaptation in a geographically widespread population and/or because of intrinsic adaptation to the state of other genes or chomosomes. In either event, hybridization between animals with differently coadapted gene or chromosomal complexes can result in a decrease in fertility, viability, etc. in the initial hybrids and especially in later generations. This is known as an outbreeding depression. Moreover, releasing animals not adapted to the local environment can seriously hamper the effectiveness of a reintroduction program, and hybridization can also destroy the local adaptation. Coadapted gene complexes are best detected through studies on na…

Sponge proteins are more similar to those of Homo sapiens than to Caenorhabditis elegans

2000

We compared 42 phylogenetically conserved proteins from four marine sponges [Porifera] with almost the complete set of Caenorhabditis elegans proteins and all known proteins from humans. The majority of the sponge proteins are significantly more similar to human than to C. elegans orthologues/homologues. This finding reflects the accelerated evolutionary rate in the C. elegans lineage, since sponges split off first from the common ancestor of all multicellular animals. Furthermore, three sponge/human proteins were not found in C. elegans: (2–5)A synthetase, DNA repair helicase and lens βγ -crystallin. Sponges are the source of the most ancient proteins already present in the common ancestor…